The present book, consists of nine chapters dealing with analysis and applications of fiber optic ring resonator (FORR). The main purpose of using an FORR is to design an optical sensor to measure physical quantities including different type of sensing devices.First, in chapter 1, the types of couplers used in resonators along with their characteristics, construction, light transmission, and the parameters are presented. Also, the theory and structure of the FORR and various applications of optical fiber in industry have been investigated.To analyze the applications of the FORR as a sensor,...